Project title: Enhancing Partner Services among Men Who Have Sex with Men Living With HIV: A Pilot Randomized Controlled Trial Despite global efforts to control HIV among key populations, new infections among men who have sex with men (MSM) are still increasing. To deal with this challenge, HIV prevention strategies with high efficacy are urgently needed. Partner services (PS), the process of informing potential risk of exposure to sexual partners, is a cornerstone of HIV prevention. PS are important for identifying cases, reducing re-infection rates, promoting linkage to care, and reducing costs. However, barriers from both health providers and index cases limit the efficacy of PS. As a result, PS is underused in many countries, including China where only 16% of index HIV case spouses were notified. Crowdsourcing can be used to improve the effectiveness of PS. Crowdsourcing is an approach that obtains solutions from communities. Crowdsourcing has been used effectively in public health to improve HIV testing, promote condom use, and monitor outbreaks. As a bottom-up approach, crowdsourcing can effectively engage MSM and other stakeholders to contribute their voices to enhance understanding of HIV PS and design participant-oriented interventions. Crowdsourced messages developed for PS may resonate more strongly with MSM compared to traditional PS messages. In turn, this could lead to increased community participation and acceptance of HIV PS, improving the effectiveness of HIV PS. We hypothesize that a crowdsourced HIV PS approach is feasible and acceptable. We also hypothesize that, as compared to conventional PS using referral cards (standard of care in China), will yield: a) more sexual partners reporting for HIV testing, and b) more sexual partners with confirmed HIV. Our multi-disciplinary research team brings together crowdsourcing and PS experience, a history of working with MSM in China, and a rich local infrastructure for HIV research, to investigate the following aims: (1) to develop a crowdsourced PS intervention for Chinese MSM using open contests; (2) to test the feasibility, acceptability and pilot the preliminary impact of crowdsourced PS with conventional PS on promoting HIV testing uptake among partners of newly identified MSM cases using a pilot randomized controlled trial. In this pilot project, we will first use open contests to develop a crowdsourced PS intervention for Chinese MSM, then we will conduct a pilot RCT in which index MSM cases are randomized to receive crowdsourced intervention or standard of care in a ratio of 2:1. The project will develop crowdsourced intervention strategies for promoting HIV PS, and collect preliminary data for a full RCT that aims to further evaluate the efficacy and cost-effectiveness of crowdsourced PS in multiple Chinese cities. ?